occt/src/Quantity/Quantity_Color.hxx

// Created by: NW,JPB,CAL
// Copyright (c) 1991-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Quantity_Color_HeaderFile
#define _Quantity_Color_HeaderFile

#include <Standard.hxx>
#include <Standard_DefineAlloc.hxx>
#include <Standard_Handle.hxx>
#include <Standard_ShortReal.hxx>

#include <Quantity_NameOfColor.hxx>
#include <Quantity_TypeOfColor.hxx>
#include <TCollection_AsciiString.hxx>
#include <NCollection_Vec4.hxx>

//! This class allows the definition of an RGB color as triplet of 3 normalized floating point values (red, green, blue).
//!
//! Although Quantity_Color can be technically used for pass-through storage of RGB triplet in any color space,
//! other OCCT interfaces taking/returning Quantity_Color would expect them in linear space.
//! Therefore, take a look into methods converting to and from non-linear sRGB color space, if needed;
//! for instance, application usually providing color picking within 0..255 range in sRGB color space.
class Quantity_Color
{
public:

  DEFINE_STANDARD_ALLOC

  //! Creates Quantity_NOC_YELLOW color (for historical reasons).
  Quantity_Color() : myRgb (valuesOf (Quantity_NOC_YELLOW, Quantity_TOC_RGB)) {}

  //! Creates the color from enumeration value.
  Quantity_Color (const Quantity_NameOfColor theName) : myRgb (valuesOf (theName, Quantity_TOC_RGB)) {}

  //! Creates a color according to the definition system theType.
  //! Throws exception if values are out of range.
  Standard_EXPORT Quantity_Color (const Standard_Real theC1,
                                  const Standard_Real theC2,
                                  const Standard_Real theC3,
                                  const Quantity_TypeOfColor theType);

  //! Define color from linear RGB values.
  Standard_EXPORT explicit Quantity_Color (const NCollection_Vec3<float>& theRgb);

  //! Returns the name of the nearest color from the Quantity_NameOfColor enumeration.
  Standard_EXPORT Quantity_NameOfColor Name() const;

  //! Updates the color from specified named color.
  void SetValues (const Quantity_NameOfColor theName) { myRgb = valuesOf (theName, Quantity_TOC_RGB); }

  //! Return the color as vector of 3 float elements.
  const NCollection_Vec3<float>& Rgb () const { return myRgb; }

  //! Return the color as vector of 3 float elements.
  operator const NCollection_Vec3<float>&() const { return myRgb; }

  //! Returns in theC1, theC2 and theC3 the components of this color
  //! according to the color system definition theType.
  Standard_EXPORT void Values (Standard_Real& theC1,
                               Standard_Real& theC2,
                               Standard_Real& theC3,
                               const Quantity_TypeOfColor theType) const;

  //! Updates a color according to the mode specified by theType.
  //! Throws exception if values are out of range.
  Standard_EXPORT void SetValues (const Standard_Real theC1,
                                  const Standard_Real theC2,
                                  const Standard_Real theC3,
                                  const Quantity_TypeOfColor theType);

  //! Returns the Red component (quantity of red) of the color within range [0.0; 1.0].
  Standard_Real Red() const { return myRgb.r(); }

  //! Returns the Green component (quantity of green) of the color within range [0.0; 1.0].
  Standard_Real Green() const { return myRgb.g(); }

  //! Returns the Blue component (quantity of blue) of the color within range [0.0; 1.0].
  Standard_Real Blue() const { return myRgb.b(); }

  //! Returns the Hue component (hue angle) of the color
  //! in degrees within range [0.0; 360.0], 0.0 being Red.
  //! -1.0 is a special value reserved for grayscale color (S should be 0.0)
  Standard_Real Hue() const { return Convert_LinearRGB_To_HLS (myRgb)[0]; }

  //! Returns the Light component (value of the lightness) of the color within range [0.0; 1.0].
  Standard_Real Light() const { return Convert_LinearRGB_To_HLS (myRgb)[1]; }

  //! Increases or decreases the intensity (variation of the lightness).
  //! The delta is a percentage. Any value greater than zero will increase the intensity.
  //! The variation is expressed as a percentage of the current value.
  Standard_EXPORT void ChangeIntensity (const Standard_Real theDelta);

  //! Returns the Saturation component (value of the saturation) of the color within range [0.0; 1.0].
  Standard_Real Saturation() const { return Convert_LinearRGB_To_HLS (myRgb)[2]; }

  //! Increases or decreases the contrast (variation of the saturation).
  //! The delta is a percentage. Any value greater than zero will increase the contrast.
  //! The variation is expressed as a percentage of the current value.
  Standard_EXPORT void ChangeContrast (const Standard_Real theDelta);

  //! Returns TRUE if the distance between two colors is greater than Epsilon().
  Standard_Boolean IsDifferent (const Quantity_Color& theOther) const { return (SquareDistance (theOther) > Epsilon() * Epsilon()); }

  //! Alias to IsDifferent().
  Standard_Boolean operator!=  (const Quantity_Color& theOther) const { return IsDifferent (theOther); }

  //! Returns TRUE if the distance between two colors is no greater than Epsilon().
  Standard_Boolean IsEqual    (const Quantity_Color& theOther) const { return (SquareDistance (theOther) <= Epsilon() * Epsilon()); }

  //! Alias to IsEqual().
  Standard_Boolean operator== (const Quantity_Color& theOther) const { return IsEqual (theOther); }
  
  //! Returns the distance between two colors. It's a value between 0 and the square root of 3 (the black/white distance).
  Standard_Real Distance (const Quantity_Color& theColor) const
  {
    return (NCollection_Vec3<Standard_Real> (myRgb) - NCollection_Vec3<Standard_Real> (theColor.myRgb)).Modulus();
  }

  //! Returns the square of distance between two colors.
  Standard_Real SquareDistance (const Quantity_Color& theColor) const
  {
    return (NCollection_Vec3<Standard_Real> (myRgb) - NCollection_Vec3<Standard_Real> (theColor.myRgb)).SquareModulus();
  }

  //! Returns the percentage change of contrast and intensity between this and another color.
  //! <DC> and <DI> are percentages, either positive or negative.
  //! The calculation is with respect to this color.
  //! If <DC> is positive then <me> is more contrasty.
  //! If <DI> is positive then <me> is more intense.
  Standard_EXPORT void Delta (const Quantity_Color& theColor,
                              Standard_Real& DC, Standard_Real& DI) const;

  //! Returns the value of the perceptual difference between this color
  //! and @p theOther, computed using the CIEDE2000 formula.
  //! The difference is in range [0, 100.], with 1 approximately corresponding
  //! to the minimal percievable difference (usually difference 5 or greater is
  //! needed for the difference to be recognizable in practice).
  Standard_EXPORT Standard_Real DeltaE2000 (const Quantity_Color& theOther) const;

public:

  //! Returns the color from Quantity_NameOfColor enumeration nearest to specified RGB values.
  static Quantity_NameOfColor Name (const Standard_Real theR, const Standard_Real theG, const Standard_Real theB)
  {
    const Quantity_Color aColor (theR, theG, theB, Quantity_TOC_RGB);
    return aColor.Name();
  }

  //! Returns the name of the color identified by the given Quantity_NameOfColor enumeration value.
  Standard_EXPORT static Standard_CString StringName (const Quantity_NameOfColor theColor);

  //! Finds color from predefined names.
  //! For example, the name of the color which corresponds to "BLACK" is Quantity_NOC_BLACK.
  //! Returns FALSE if name is unknown.
  Standard_EXPORT static Standard_Boolean ColorFromName (const Standard_CString theName, Quantity_NameOfColor& theColor);

  //! Finds color from predefined names.
  //! @param theColorNameString the color name
  //! @param theColor a found color
  //! @return false if the color name is unknown, or true if the search by color name was successful
  static Standard_Boolean ColorFromName (const Standard_CString theColorNameString, Quantity_Color& theColor)
  {
    Quantity_NameOfColor aColorName = Quantity_NOC_BLACK;
    if (!ColorFromName (theColorNameString, aColorName))
    {
      return false;
    }
    theColor = aColorName;
    return true;
  }

public:
  //!@name Routines converting colors between different encodings and color spaces

  //! Parses the string as a hex color (like "#FF0" for short sRGB color, or "#FFFF00" for sRGB color)
  //! @param theHexColorString the string to be parsed
  //! @param theColor a color that is a result of parsing
  //! @return true if parsing was successful, or false otherwise
  Standard_EXPORT static bool ColorFromHex (const Standard_CString theHexColorString, Quantity_Color& theColor);

  //! Returns hex sRGB string in format "#FFAAFF".
  static TCollection_AsciiString ColorToHex (const Quantity_Color& theColor,
                                             const bool theToPrefixHash = true)
  {
    NCollection_Vec3<Standard_ShortReal> anSRgb = Convert_LinearRGB_To_sRGB ((NCollection_Vec3<Standard_ShortReal> )theColor);
    NCollection_Vec3<Standard_Integer> anSRgbInt (anSRgb * 255.0f + NCollection_Vec3<Standard_ShortReal> (0.5f));
    char aBuff[10];
    Sprintf (aBuff, theToPrefixHash ? "#%02X%02X%02X" : "%02X%02X%02X",
             anSRgbInt.r(), anSRgbInt.g(), anSRgbInt.b());
    return aBuff;
  }

  //! Converts sRGB components into HLS ones.
  Standard_EXPORT static NCollection_Vec3<float> Convert_sRGB_To_HLS (const NCollection_Vec3<float>& theRgb);

  //! Converts HLS components into RGB ones.
  Standard_EXPORT static NCollection_Vec3<float> Convert_HLS_To_sRGB (const NCollection_Vec3<float>& theHls);

  //! Converts Linear RGB components into HLS ones.
  static NCollection_Vec3<float> Convert_LinearRGB_To_HLS (const NCollection_Vec3<float>& theRgb)
  {
    return Convert_sRGB_To_HLS (Convert_LinearRGB_To_sRGB (theRgb));
  }

  //! Converts HLS components into linear RGB ones.
  static NCollection_Vec3<float> Convert_HLS_To_LinearRGB (const NCollection_Vec3<float>& theHls)
  {
    return Convert_sRGB_To_LinearRGB (Convert_HLS_To_sRGB (theHls));
  }

  //! Converts linear RGB components into CIE Lab ones.
  Standard_EXPORT static NCollection_Vec3<float> Convert_LinearRGB_To_Lab (const NCollection_Vec3<float>& theRgb);

  //! Converts CIE Lab components into CIE Lch ones.
  Standard_EXPORT static NCollection_Vec3<float> Convert_Lab_To_Lch (const NCollection_Vec3<float>& theLab);

  //! Converts CIE Lab components into linear RGB ones.
  //! Note that the resulting values may be out of the valid range for RGB.
  Standard_EXPORT static NCollection_Vec3<float> Convert_Lab_To_LinearRGB (const NCollection_Vec3<float>& theLab);

  //! Converts CIE Lch components into CIE Lab ones.
  Standard_EXPORT static NCollection_Vec3<float> Convert_Lch_To_Lab (const NCollection_Vec3<float>& theLch);

  //! Convert the color value to ARGB integer value, with alpha equals to 0.
  //! So the output is formatted as 0x00RRGGBB.
  //! Note that this unpacking does NOT involve non-linear sRGB -> linear RGB conversion,
  //! as would be usually expected for RGB color packed into 4 bytes.
  //! @param theColor [in] color to convert
  //! @param theARGB [out] result color encoded as integer
  static void Color2argb (const Quantity_Color& theColor,
                          Standard_Integer& theARGB)
  {
    const NCollection_Vec3<Standard_Integer> aColor (static_cast<Standard_Integer> (255.0f * theColor.myRgb.r() + 0.5f),
                                                     static_cast<Standard_Integer> (255.0f * theColor.myRgb.g() + 0.5f),
                                                     static_cast<Standard_Integer> (255.0f * theColor.myRgb.b() + 0.5f));
    theARGB = (((aColor.r() & 0xff) << 16)
             | ((aColor.g() & 0xff) << 8)
             |  (aColor.b() & 0xff));
  }

  //! Convert integer ARGB value to Color. Alpha bits are ignored.
  //! Note that this packing does NOT involve linear -> non-linear sRGB conversion,
  //! as would be usually expected to preserve higher (for human eye) color precision in 4 bytes.
  static void Argb2color (const Standard_Integer theARGB,
                          Quantity_Color& theColor)
  {
    const NCollection_Vec3<Standard_Real> aColor (static_cast <Standard_Real> ((theARGB & 0xff0000) >> 16),
                                                  static_cast <Standard_Real> ((theARGB & 0x00ff00) >> 8),
                                                  static_cast <Standard_Real> ((theARGB & 0x0000ff)));
    theColor.SetValues (aColor.r() / 255.0, aColor.g() / 255.0, aColor.b() / 255.0, Quantity_TOC_sRGB);
  }

  //! Convert linear RGB component into sRGB using OpenGL specs formula (double precision), also known as gamma correction.
  static Standard_Real Convert_LinearRGB_To_sRGB (Standard_Real theLinearValue)
  {
    return theLinearValue <= 0.0031308
         ? theLinearValue * 12.92
         : Pow (theLinearValue, 1.0/2.4) * 1.055 - 0.055;
  }

  //! Convert linear RGB component into sRGB using OpenGL specs formula (single precision), also known as gamma correction.
  static float Convert_LinearRGB_To_sRGB (float theLinearValue)
  {
    return theLinearValue <= 0.0031308f
         ? theLinearValue * 12.92f
         : powf (theLinearValue, 1.0f/2.4f) * 1.055f - 0.055f;
  }

  //! Convert sRGB component into linear RGB using OpenGL specs formula (double precision), also known as gamma correction.
  static Standard_Real Convert_sRGB_To_LinearRGB (Standard_Real thesRGBValue)
  {
    return thesRGBValue <= 0.04045
         ? thesRGBValue / 12.92
         : Pow ((thesRGBValue + 0.055) / 1.055, 2.4);
  }

  //! Convert sRGB component into linear RGB using OpenGL specs formula (single precision), also known as gamma correction.
  static float Convert_sRGB_To_LinearRGB (float thesRGBValue)
  {
    return thesRGBValue <= 0.04045f
         ? thesRGBValue / 12.92f
         : powf ((thesRGBValue + 0.055f) / 1.055f, 2.4f);
  }

  //! Convert linear RGB components into sRGB using OpenGL specs formula.
  template<typename T>
  static NCollection_Vec3<T> Convert_LinearRGB_To_sRGB (const NCollection_Vec3<T>& theRGB)
  {
    return NCollection_Vec3<T> (Convert_LinearRGB_To_sRGB (theRGB.r()),
                                Convert_LinearRGB_To_sRGB (theRGB.g()),
                                Convert_LinearRGB_To_sRGB (theRGB.b()));
  }

  //! Convert sRGB components into linear RGB using OpenGL specs formula.
  template<typename T>
  static NCollection_Vec3<T> Convert_sRGB_To_LinearRGB (const NCollection_Vec3<T>& theRGB)
  {
    return NCollection_Vec3<T> (Convert_sRGB_To_LinearRGB (theRGB.r()),
                                Convert_sRGB_To_LinearRGB (theRGB.g()),
                                Convert_sRGB_To_LinearRGB (theRGB.b()));
  }

  //! Convert linear RGB component into sRGB using approximated uniform gamma coefficient 2.2.
  static float Convert_LinearRGB_To_sRGB_approx22 (float theLinearValue) { return powf (theLinearValue, 2.2f); }

  //! Convert sRGB component into linear RGB using approximated uniform gamma coefficient 2.2
  static float Convert_sRGB_To_LinearRGB_approx22 (float thesRGBValue) { return powf (thesRGBValue, 1.0f/2.2f); }

  //! Convert linear RGB components into sRGB using approximated uniform gamma coefficient 2.2
  static NCollection_Vec3<float> Convert_LinearRGB_To_sRGB_approx22 (const NCollection_Vec3<float>& theRGB)
  {
    return NCollection_Vec3<float> (Convert_LinearRGB_To_sRGB_approx22 (theRGB.r()),
                                    Convert_LinearRGB_To_sRGB_approx22 (theRGB.g()),
                                    Convert_LinearRGB_To_sRGB_approx22 (theRGB.b()));
  }

  //! Convert sRGB components into linear RGB using approximated uniform gamma coefficient 2.2
  static NCollection_Vec3<float> Convert_sRGB_To_LinearRGB_approx22 (const NCollection_Vec3<float>& theRGB)
  {
    return NCollection_Vec3<float> (Convert_sRGB_To_LinearRGB_approx22 (theRGB.r()),
                                    Convert_sRGB_To_LinearRGB_approx22 (theRGB.g()),
                                    Convert_sRGB_To_LinearRGB_approx22 (theRGB.b()));
  }

  //! Converts HLS components into sRGB ones.
  static void HlsRgb (const Standard_Real theH, const Standard_Real theL, const Standard_Real theS,
                      Standard_Real& theR, Standard_Real& theG, Standard_Real& theB)
  {
    const NCollection_Vec3<float> anRgb = Convert_HLS_To_sRGB (NCollection_Vec3<float> ((float )theH, (float )theL, (float )theS));
    theR = anRgb[0];
    theG = anRgb[1];
    theB = anRgb[2];
  }

  //! Converts sRGB components into HLS ones.
  static void RgbHls (const Standard_Real theR, const Standard_Real theG, const Standard_Real theB,
                      Standard_Real& theH, Standard_Real& theL, Standard_Real& theS)
  {
    const NCollection_Vec3<float> aHls = Convert_sRGB_To_HLS (NCollection_Vec3<float> ((float )theR, (float )theG, (float )theB));
    theH = aHls[0];
    theL = aHls[1];
    theS = aHls[2];
  }

public:

  //! Returns the value used to compare two colors for equality; 0.0001 by default.
  Standard_EXPORT static Standard_Real Epsilon();

  //! Set the value used to compare two colors for equality.
  Standard_EXPORT static void SetEpsilon (const Standard_Real theEpsilon);

  //! Dumps the content of me into the stream
  Standard_EXPORT void DumpJson (Standard_OStream& theOStream, Standard_Integer theDepth = -1) const;

private:

  //! Returns the values of a predefined color according to the mode.
  Standard_EXPORT static NCollection_Vec3<float> valuesOf (const Quantity_NameOfColor theName,
                                                           const Quantity_TypeOfColor theType);

private:

  NCollection_Vec3<float> myRgb;

};

#endif // _Quantity_Color_HeaderFile